Research on Phase Noise Measurement Algorithm of Quadrature Digital Demodulation

Phase noise measures the frequency stability of the signal source in a short time, and it reflects the phase and frequency fluctuation caused by noise. At present, the commonly used phase noise measurement techniques at home and abroad include PLL phase-locked phase detection method and orthogonal digital demodulation method. The phase measurement method of orthogonal digital demodulation avoids the deterioration of near-end sensitivity and the limitation of measurement speed caused by PLL, and is more beneficial to improve the function and performance of phase noise measurement. The purpose of this paper is to study the key algorithms involved in high sensitivity phase noise measurement based on quadrature digital demodulation. First of all, the technical scheme of the orthogonal digital demodulation method is analyzed; then, the key algorithms are studied and simulated; finally, the algorithm is summarized and analyzed to verify its feasibility and practicability.